Various efforts are being made to achieve carbon neutrality worldwide. In particular, the cement industry, producing the third largest amount of carbon dioxide in the industrial sector, could be a key sector in achieving carbon neutrality. While, cement emits a lot of carbon dioxide from the manufacturing process, it efficiently store carbon dioxide through carbonation reactions in a moisture environment. Carbonation reactions can be divided into pre- and post- hardening stages. Unlike natural carbonation after hardening that occurs over a long period of time, it is known that the mineral carbonation reaction before hardening reacts quickly in the initial age and has the advantage of initial curing. In this study, relationship between workability, CO2 fixed amount, and compressive strength of cement mortar has been evaluated using CO2 microbubble water, which has dissolved carbon dioxide compared to conventional carbonated water. From the extensive experimental test, the CO2 concentration of the CO2 microbubble mixed water observed about 400 ppm. There was no improvement in the workability of cement mortar using CO2 microbubble mixed water, but about 2.5% of the CO2 fixing capacity has been observed. For compressive strength, it was confirmed that the strength increased by up to about 197% on the 3rd day and by about 123% on the 28th day, confirming the potential for long-term use. It is concluded that CO2 can be effectively stored through the CO2 fixing ability of cement mortar using the CO2 microbubble mixed water. This method demonstrates the potential for CO2 reduction, as it enhances compressive strength and reduces the required unit cement amount.